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Does The Critical Shields Stress For Sediment Transport Depend On Channel-Bed Slope?, Ishraq Alfadhli, Shu-Qing Yang, Muttucumaru Sivakumar
Does The Critical Shields Stress For Sediment Transport Depend On Channel-Bed Slope?, Ishraq Alfadhli, Shu-Qing Yang, Muttucumaru Sivakumar
Ishraq Hamdan Alfadhli
This paper investigates why the observed critical Shields stress for incipient sediment motion deviates from the Shields curve. This deviation is often described in the literature as due to measurement errors and non-uniformity of channel-bed slope or flows. On the contrary, this paper hypothesises the deviation as due to the presence of vertical velocity in open channel flows. We found that the existence of vertical velocity in non-uniform flows can lead to the deviation of critical shear stress from the standard Shield's diagram that is valid only in uniform flows, and the channel bed slope could not contribute to the …
Significant Improvement In The Critical Current Density Of In Situ Mgb2 By Excess Mg Addition, R Zeng, L Lu, Jianli Wang, J Horvat, W Li, Dongqi Shi, S Dou, M Tomsic, M Rindfleisch
Significant Improvement In The Critical Current Density Of In Situ Mgb2 By Excess Mg Addition, R Zeng, L Lu, Jianli Wang, J Horvat, W Li, Dongqi Shi, S Dou, M Tomsic, M Rindfleisch
Jianli Wang
We present a detailed analysis of the effects of excess Mg on the lattice parameters, the critical temperature (Tc), the critical current (Jc), the irreversibility field (Hirr), and the upper critical field (Hc2) of MgB2 bulks and wires produced by an in situ solid-state reaction method and the powder-in-tube method, respectively. It was found that Jc, Hirr, and Hc2 were significantly enhanced for Mg excess samples. All these properties were highly sensitive to the processing temperature for Mg excess samples, while there was only a weak dependence on processing temperature for normal ones. The Tc variation for the 10% Mg …
Identification Of Factors Limiting The Critical Current Density In Mgb2 _Xcx Superconductors At Low Magnetic Fields, Olga Shcherbakova, Alexey Pan, Jianli Wang, Andrey Shcherbakov, S. Dou, David Wexler
Identification Of Factors Limiting The Critical Current Density In Mgb2 _Xcx Superconductors At Low Magnetic Fields, Olga Shcherbakova, Alexey Pan, Jianli Wang, Andrey Shcherbakov, S. Dou, David Wexler
Jianli Wang
Structural analysis and electromagnetic measurements have been performed on a range of samples prepared by the liquid mixing approach to doping MgB2 are sugar, malic acid, and polycarbosilane. The results obtained have allowed us to clarify the contributions of the factors limiting critical current at low magnetic fields in doped MgB2.